Explosive California wildfires have tainted local air quality this summer with soot, ash and tiny particles that can trigger respiratory problems and make breathing outdoors unhealthy.

But while the thick smoke can be an obvious reminder to stay indoors, wildfires also create carbon monoxide, an invisible, more subtle threat that travels long distances carrying the potential of degrading air quality in other states.

According to new satellite data, carbon monoxide emitted from massive wildfires raging in Northern and Southern California in the past few months is being lofted high into the atmosphere, catching an updraft that sends waves of toxic gas beyond California’s borders into Nevada, Idaho, Utah, New Mexico, Texas, and also the Midwest, the Northeast and Canada.

The high levels of the noxious gas — a product of burning grasses and trees more commonly associated with the combustion of gasoline in automobiles emitted from tailpipes — come with a warning from scientists at NASA’s Jet Propulsion Laboratory of the California Institute of Technology in Pasadena.

“Emissions in one state can affect air quality in another,” said Vivienne Payne, a JPL research scientist who has studied the data, during a phone interview Wednesday from her office at the campus in La Cañada Flintridge. “Air quality doesn’t respect state borders.”

When inhaled, carbon monoxide reduces the amount of oxygen in the blood and can cause chest pains, headaches and impaired reaction timing.

Data pouring in from the Atmospheric Infrared Sounder or AIRS instrument on board NASA’s Aqua satellite show high concentrations of carbon monoxide from the Carr fire near Shasta and Redding, the Mendocino Complex fire, and locally from the Cranston fire near Idyllwild, Valley fire in Forest Falls and the Holy fire still burning in Trabuco Canyon between July 30 and Aug. 8.

The animation shows concentrations of carbon monoxide (in orange and red) from California’s massive wildfires drifting east across the United States between July 30 and Aug. 7. (video courtesy of JPL-Caltech).

A time-lapse video from JPL shows concentrations as high as 270 parts per billion per volume of air moving east, with the highest levels in red and orange. Once over the Midwest, the carbon monoxide dilutes with air and the map shows a yellow mass of lower concentrations, but they climb to about 130 parts per billion in the Great Lakes region, Texas and New York.

“The point is: Pollution being produced from fires in the western states doesn’t just affect local air quality,” Payne, who works in JPL’s Earth Science division, said. “It is possible that it (carbon monoxide) could be transported downward far from the original source.”

Health impacts unclear

Do those carbon monoxide clouds sink down to the lower atmosphere where people are living and breathing?

It’s possible but has not been confirmed at the Lab whether the carbon monoxide clouds over other states are reaching lower levels where people are exposed to it, Payne said.

The AIRS satellite measures carbon monoxide in the mid-troposphere or about 4.3 miles high, she said. The compound lasts for about a month, making it trackable.

“Depending on what the winds are doing will determine if it can be transported down near the ground,” she said. “But I am not aware there is evidence of it coming down.”

Patrick Chandler, spokesman for the South Coast Air Quality Management District, said it’s unlikely.

“In most circumstances, long range transportation of carbon monoxide (CO) does not elevate surface concentrations to unhealthful levels,” he said.

However, on Thursday, residents of Washington D.C and Baltimore woke up to the odor of forest fires in the air, even though no local forests were burning.

Air quality expert Joel Dreessen from Maryland’s Department of Environment told the Washington Post the smoke is coming from wildfires in the West and is affecting local air quality.

Dreessen said the smoke had been carried into the nation’s capital and environs most likely by jet stream winds in the upper atmosphere and had “made its way to the surface in noticeable fashion.”

The components of the smoke “detected in elevated quantities” include fine particulate matter, black carbon and carbon monoxide, Dreessen told the Post. The added pollution from California fires is compounding the damaging effects of ground-level ozone on breathing, elevated by high temperatures and stagnant air, the Maryland agency reported.

Global travel

Air pollution traveling long distances is not a new phenomenon, according to Payne.

Steve Scauzillo covers environment and transportation for the Southern California News Group. He has won two journalist of the year awards from the Angeles Chapter of the Sierra Club and is a recipient of the Aldo Leopold Award for Distinguished Editorial Writing on environmental issues. Steve studied biology/chemistry when attending East Meadow High School and Nassau College in New York (he actually loved botany!) and then majored in social ecology at UCI until switching to journalism. He also earned a master's degree in media from Cal State Fullerton. He has been an adjunct professor since 2005. Steve likes to take the train, subway and bicycle – sometimes all three – to assignments and the newsroom. He is married to Karen E. Klein, a former journalist with Los Angeles Daily News, L.A. Times, Bloomberg and the San Fernando Valley Business Journal and now vice president of content management for a bank. They have two grown sons, Andy and Matthew. They live in Pasadena. Steve recently watched all of “Star Trek” the remastered original season one on Amazon, so he has an inner nerd.